Lab Report Iodination Of Acetone

Lab Report
Iodination of Acetone
Temperature as a Variable

Objective

The objective of this lab is to determine the energy of activation of the iodination of acetone. This will be done by performing the reaction at differing temperatures. The same reaction orders we obtained for the previous lab will be incorporated into this experiment. The equation Ea = -8.31 x slope of ln k vs. 1/T(K) will be used to determine the energy of activation required for this this reaction.

Hypothesis :

We predict that the change in temperature will affect the timing of the reaction because when the temperature is higher, there's more energy and less energy at lower temperatures and atoms move around more at higher temperatures because of
the kinetic energy. This means that keeping everything constant (reactants and their volumes), only the k value can change. As far as the energy of activation goes, there is no information provided to us so we have no prediction at this time and we will have to use the data we acquire to calculate the resulting energy of activation.

Equipment

• 4.0 M Acetone • 1.0 M HCL • 0.0050 M I2 • Distilled Water • Three 50mL Burette • Two Double Burette Clamps • Support Stand • Three small funnels • 50mL graduated cylinder • 250mL Erlenmeyer flask • Three 100mL Beakers • Eight test tubes • Thermometer • Stopwatch • Gloves • Safety Glasses • 500 mL beaker • A heater, with a magnet.

Experimental Procedure

1. We prepared for the lab by obtaining all the necessary materials on the equipment list.

2. With the funnels, we poured 50mL of the following reactants: Acetone, HCL, and Iodine; in their respective burets.

3. We followed the normal procedure by putting 20mL water, 10mL HCl and 10mL acetone in an Erlenmeyer flask and then added 10mL iodine to it and started timing the reaction. We used this data for our controlled at room temperature (26 degrees Celsius).

4.
Then we poured water in the 500 mL beaker that was at room temperature, and put ice cubes into it to get it to a desired temperature (22 degrees Celsius).

5. Into a graduated cylinder, we carefully poured 10mL of Acetone from the buret, 10mL of HCL, and 20mL of distilled water. Once we had those three in the gradated cylinder we put 10mL of iodine in a test tube and we placed both in the 500 mL beaker with thermometers in each solution to ensure that they were all the same temperature when we added the iodine. As soon as all the solutions reached the desired temperature (22 degrees Celsius) we poured the iodine into the graduated cylinder and started timing the reaction.

6. As soon as the reaction stopped, we stopped the stopwatch, recorded the time and carefully poured the solution into a test tube and recorded the temperature.

7. We emptied the beaker of the previous equipment leaving the water and put the beaker with water onto a heater with a magnetic stirring rod and heated it up to the desired temperature (30 degrees Celsius).

8. We repeated step 5 in the procedure to 30 degrees Celsius and then repeated step 6 and recorded the time and
temperature.

Data

DETERMINATION OF ENERGY OF ACTIVATION

| | |TEMPERATURE °C |TEMPERATURE Kelvin |
|Time for reaction at about 22 °C |279 sec |22 °C |295 K |
|Time for reaction at about °C |161 sec |30 °C |303 K |
|Time for reaction at room temp |203 sec |26 °C |299 K |

| |TIME |TEMPERATURE |TEMPERATURE |
| |Seconds |°C |Kelvin |
|Below Ambient |279 sec |22 °C |295 K |
|Above Ambient |161 sec |30 °C |303 K |
|Ambient |203 sec |26 °C |299 K |

RATE CONSTANT

| |RATE |k |In k |1/T(K) |
|~22 °C |3.58 x10-6 |1.25 x10-4 |-8.987 |3.39 x10-3
|
|~30°C |6.21 x10-6 |2.17 x10-4 |-8.435 |3.30 x10-3 |
|~26°C |4.93 x10-6 |1.73 x10-4 |-8.662 |3.34 x10-3 |

Equations 1) Rate = - ∆(I2) /∆t 2) k = rate/(acetone)m(I2)n(H+)p

CALCULATIONS

For rates,

@ 22 degrees C => .001/279= 3.58 x10-6 @ 30 degrees C => .001/161= 6.21 x10-6 @ 26 degrees C => .001/203= 4.93 x10-6

For k,

@ 22 degrees C => (3.58 x10-6)/(.8)1.14(.001).189(.2)1.24 = 1.25 x10-4 @ 30 degrees C => (6.21 x10-6)/(.8)1.14(.001).189(.2)1.24 = 2.17 x10-4 @ 26 degrees C => (4.93 x10-6)/(.8)1.14(.001).189(.2)1.24 = 1.73 x10-4

Graph of ln k vs. 1/T

[pic]

slope of ln k vs. 1/T(K) = -6194.9

by equation 2: (Energy of Activation) Ea = -8.31 x -6194.9 = 51479.6 joules

CONCLUSION

Our hypothesis was correct in that the reaction changed accordingly to the temperature change, faster reaction time in a higher temperature and a slower reaction in a lower temperature. This must be due to the higher temperature providing more energy for the reaction. After gathering our data, we found that since the reaction time changed while keeping a constant mixture, the rate had to change and if the rate changed, it had to be the k value that had changed because we kept all the reactants and their volumes constant. After utilizing all the data we have gathered, we arrived at the conclusion that the energy of activation for the iodination of acetone for our experiment is 51,479.6 joules as per equation 2 from the lab manual.